Right-angle bur-mandrel.



No. 825,271. PATENTED JULY 3, 1906. G. N. GUTHRIE, JR.

RIGHT ANGLE BUR MANDREL.

APPLIUATION FILED JUNE 15. 1905.

GEORGE N. GUTHRIE, JR, OF COOKEVILLE, TENNESSEE.

RIGHT-ANGLE BUR-MANDREL.

Specification of Letters Patent.

Patented July 3, 1906.

Anplication filed June 15,1905. Serial No. 265,462.

To all whom it may concern.-

Be it known that I, GEORGE N. GUTHRIE, Jr., a citizen of the United States, residing at Cookeville, in the county of Putnam and State of Tennessee, have invented certain new and useful Improvements in Right Angle Bur-Mandrels; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in means for securing a dental tool or bur in the outer or tool-carrying end of a spindle designed to be rotatively mounted in a dental handpiece and it consists in the construction and combination of devices hereinafter described and claimed.

In the accompanying drawings, Figure 1 is a side elevation of a dental bur fastened within the improved bur mandrel. Fig. 2 is partly an elevation of the same and partly a section taken on a plane intersecting the fastening means. Fig. 3 is a transverse sectional view of the same, taken on a plane at right angles to that of Fig. 2 and intersecting the fastening means. Fig. 4 is a perspective view of the inner end of the bur. Fig. 5 is an end view of the bur-receiving socket. Fig. 6 is a detail sectional view. Fig. 7 is a longitudinal sectional view through the same, and Fig. 8 is a detail of the rotary locking-sleeve.

Referring to the drawings by numeral, 1 denotes a dental bur of a form used on rightangle handpieces of dental engines, 2 denotes the rotary spindle of a straight handpiece of a dental engine, and 3 denotes my improved fastening means for securing these parts together. The bur, as shown, has a cylindrical inner end and is formed adjacent thereto.

with an annular groove 4 and a flattened portion 5, which interrupts said groove, as clearly shown in Fig. 4 of the drawings. The spindle 2 is shaped at its inner end to engage the interior of the handpiece, and its outer end is enlarged and bored or hollowed to form a tubular socket 7, which is adapted to receive the inner end of the bur. Within this tubular socket 7 is formed a longitudinalextending lug or enlargement 8, adapted to engage the flattened portion 5 of the bur 1,

so as to cause the latter to rotate with it when the device is in operation. This lug or enlargement 8 is formed at one side with a notch 9, adapted to aline with the annular groove 4 in the bur when the latter is placed in the socket 7 The bur is retained orlocked in said socket by a lug or pin 10, formed upon a locking-sleeve 3, which surrounds or partially surrounds the socket 7 adjacent to a slot 12, formed in said socket to permit the tongue or lug 10 to enter the groove 4 in the bur and the notch9in the socket. The clamping-sleeve 11 is preferablyin the form of a split ring, with the locking lug or pro jection 10 disposed centrally upon its inner face opposite its opening or split portion.

It Will be seen upon reference to Fig. 3 of the drawings that when the lockingsleeve is turned so that the projection 10 will enter the notch 9 in the socket the bur 1 may be readily inserted into or removed from the socket 7 and that when said sleeve is turned to cause this projection to enter the annular groove 4; formed in the bur the latter will be retained in said socket and will be caused to rotate therewith.

The construction, use, and advantages of the invention will be readily understood from the foregoing description, taken in connection with the accompanying drawings.

It will be seen that by providing this at tachment or appliance the short burs used in the right-angled handpieces of dental engines maybe readily applied to and used upon the straight handpieoes, so that the dentist will be required to have but one set of burs.

Various changes in the form, proportion, and the minor details of construction may be resorted to without departing from the principle or sacrificing any of the advantages of this invention.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

In combination with a tool having a flattened portion on one side at one end and an annular groove interrupted by said flattened portion, a spindle having a socket at one end to receive said end of the tool and formed with a slot, an enlarged portion or lug to bear against the flattened portion'of the tool and With a notch in said lug registering With the I my hand in presence of two subscribing Witannular groove in the tool, and a rotary sleeve nesses. I on said socket, having a locking-tongue proj ecting through the slot thereof into the regl 5 istering groove and notch, substantially es Witnesses:

described. R. L. FARLEY,

In testimony whereof I have hereunto set E. D. HALLADAY.

GEORGE N. GUTHRIE, JR. 

